What is the test for determining whether a defendant is competent to plead guilty?

I dissent from that portion of the majority opinion which reverses the conviction of People v. Lang, which I would affirm. I concur in the affirmance of the other cases herein, but would hold that, where a defendant is represented by counsel who is presumed to be competent and who is charged with the responsibility of advising a defendant as to the legal implications involved in the taking of a plea of guilty, the courts are not required to make inquiry of a defendant by catechism or otherwise.